1. Field
The present embodiments relate to a dendrimer and an organic light-emitting device including an organic layer having the dendrimer.
2. Description of the Related Technology
A general organic light-emitting device includes an anode, a hole transport layer, an emission layer, an electron transport layer and a cathode, which are sequentially formed on a substrate in the order stated. In this regard, the hole transport layer, the emission layer, and the electron transport layer are organic thin films comprising organic compounds.
An organic light-emitting device is a self-emitting display device in which when a current is applied to a fluorescent or phosphorescent organic layer, electrons are combined with holes in the organic layer, thereby emitting light. Since organic light-emitting devices are lightweight, can be fabricated using simple constituent elements in an easy fabrication process, can realize high image quality, high color purity, and dynamic images, and operate with low power consumption, diverse research is being conducted into organic light-emitting devices. An organic light-emitting device may include a hole-related layer such as a hole injection layer and a hole transport layer and an electron-related layer such as an electron transport layer and an electron injection layer in addition to an organic emission layer between an anode and a cathode.
The material for forming the hole injection layer may be a material that enables to perform a solution process due to a low unit cost. Such a material may include a polymer material, which may be commercially purchased, for example, PEDOT/PSS, which is poly styrene sulfonic acid (PSS) doped poly(ethylenedioxy)thiopene (PEDOT). Also, a low molecular material that is conventionally invented may be used by being dissolved in a general solvent and by performing a solution process such as spin coating.
However, In a PEDOT/PSS composition, PSS is decomposed by reaction with electrons and thus emits a material such as sulfate to diffuse to an adjacent organic layer, for example, an emission layer. Such a diffusion of a material from the hole injection layer to the emission layer causes exciton quenching, thereby deteriorating efficiency and life-span of organic light-emitting device. Also, when a low molecular material is used in a solution process, recrystallization may occur after spin coating or the material is not uniform.
The present embodiments provide a material for forming a hole injection layer which may be dissolved in an organic solvent so as to perform a solution process and have excellent adhesive strength with ITO and IZO. Also, to the present embodiments increase molecular weight which preventing stacking due to introduction of a bulky functional group.